Patients have magnetic resonance imaging and/or positron emission tomography (PET) scans performed prior to start of therapy, 6 weeks and 16 weeks following the initiation of therapy, and 6 weeks following the completion of therapy. Each scan requires about 1-3 hours. Patients receive up to 3 different PET scans including tumor blood flow scan with H2015, tumor blood volume scan with 11CO, and glucose uptake scan with fludeoxyglucose F 18.